GB2306448A

GB2306448A - Feeding strip material

Info

Publication number: GB2306448A
Application number: GB9521575A
Authority: GB
Inventors: John Christopher Norkett
Original assignee: ACORN ENGINEERING
Current assignee: ACORN ENGINEERING
Priority date: 1995-10-20
Filing date: 1995-10-20
Publication date: 1997-05-07
Anticipated expiration: 2015-10-20
Also published as: GB2306448B; GB9521575D0

Abstract

Strip 5 is fed by a driven roller 4 and associated roller 12, both of which are covered with protective material which will not adversely affect the surface of the strip, eg its reflectivity, the drive motor (not shown) for roller 4 being controlled by pulses from an encoder (not shown) driven by an accurately machined roller 3, roller 3 forming a nip with a roller 13 which is also covererd with protective material. Grooved registering rollers (figure 6) for engaging side edges of the strip are disclosed.

Description

Strip Fending Wechanisms This invention relates to strip feeding mechanisms, and is especially applicable to feeding mechanisms having nip feeding rolls for feeding strip material into a processing machine such as a press stamping machine, where the feeding mechanism includes positioning means for controlling the feed and disposing the strip material sequentially within the press stamping machine for one or more stamping actions to produce a particular product from the strip material.Thus for example such a feeding and measuring/positioning mechanism may be used for the feeding of strip formed of light metal alloy into a press stamping machine where the light metal strip is sequentially stopped and stamped at a number of stamping stations within the machine ready for further fabrication to constitute eventually reflective and separating louvres for lighting installations.

In the press stamping of such light metal strip in the production of reflective louvres for lighting installations, it has been found that the feeding and measuring/positioning system associated therewith can involve the use of rollers which scuff and mark and otherwise adversely effect the highly prepared reflective surface of one side of the strip intended in the fully fabricated condition of the louvres to constitute a light reflecting surface of the louvres surrounding the lamp of a lighting fitting.

A common expedient to obviate the problem with such a feeding and measuring/positioning mechanism has been to provide the strip prior to its feeding into and press stamping within the press stamping machine, with a thin plastics coating on its relevant reflective surface.

However this expedient, although substantially successful in preventing damage to the reflective side of the strip, involves additional expense in its application to the strip and its subsequent removal from the partially formed louvre pieces stamped from the strip.

It is an object of the present invention to overcome or at least substantially reduce the above-mentioned problem.

In accordance with one aspect of the present invention there is provided a strip feeding and measuring/positioning mechanism comprising two pairs of nip rollers through which the strip is arranged in use to be passed, a first pair of rollers one of which is motor driven and the other of which is a load roller, both being coated with a layer of nonmarking gripping material such as a synthetic rubber, the first pair being arranged to drive the strip through the mechanism, and a second upstream pair of rollers through which the strip is arranged in use to pass prior to passing through the driving pair of rolls, the upstream pair of rollers comprising one load roller provided with a layer of non-marking gripping material such as synthetic rubber, and a measuring/positioning roller comprising an accurately machined roller of known diameter connected to a pulse encoder device connecting in turn to a drive motor of the driven roller whereby to control the same in dependence upon predetermined rotation of the measuring/positioning roll and hence the disposition of strip being fed through the mechanism.

By means of the invention, by ensuring that a side of the strip to be protected from marking, such as the reflective side thereof in relation to strip for use after fabrication in lamp louvres, is contacted only by the rollers having a non-marking surface, whilst enabling the other side of the strip to be contacted by the precision roll, (which may in practice scuff or score that surface), we have found it readily possible to feed and control the rate of feed and position of strip by means of the feeding mechanism of the apparatus without in any w.y adversely marking the reflective surface of the strip passing therethrough.

The pairs of rollers may be disposed in a horizontal plane, such that the strip pass is horizontally therebetween, and the driven roller may comprise a lower roller of the driving roller pair, and the measuring/positioning roller may comprise a lower roller of the upstream pair of rollers.

The upper load rollers of the two pairs of rollers may be mounted in blocks downwardly urged by load springs upon the two lower rollers, the mounting blocks, carrying bearings for the upper load rollers. The mounting blocks may be pivoted on a side block assembly at each end which is vertically moveable within a vertical slide, thereby providing in operation flexibility of the disposition of the upper load rollers relative to the lower rollers to accommodate variations in the strip being fed therethrough both in a side to side direction, and in a forward and back direction.

Means may be provided for raising the mounting blocks of the upper load rollers, against the action of the load springs, to lift them out of contact with the lower rollers to ensure a cessation of the driving of the strip through the mechanism for any necessary adjustment during operation.

Another problem in feeding strip through a feeding mechanism of the kind to which this invention relates has been the control of the strip in a side to side sense as it approaches and is fed through the driving mechanism and on through the associated strip processing machine, such as a press stamping machine, to which the strip is driven. Thus the strip, being fed from a reel thereof, can well have an undulating nature, and can have significant deviations from flatness, at its side edges, and can in some cases be curved across its width as well as having a tendency to bend along its length.

Attempts have been made to control side to side deviation of movement of strip as it enters and passes through the feeding mechanism and into, for example, a press stamping machine, by means of side rolls freely rotating and engaging the side edges of the strip. Such rolls have usually been provided with a peripheral indent of large width with significant shoulders on each side to contain the edges of the strip. However it has been found that these are by no means satisfactory in controlling movement of the strip and preventing undesirable variations in travel of the strip through the mechanism and subsequent machine.

It is another object of the present invention to overcome this problem.

According to a second aspect of the present invention there is provided positional guide and control means for strip travelling towards and /or out of feeding mechanism therefore, comprising a pair of freely rotatable rolls disposed one on each side of the strip, the rolls being rotatable about axes normal to the plane of the strip and each being provided with a central peripheral groove therethrough of substantially parallel sides and disposed in operation such that the strip edges engage into the groove, the groove having a width arranged to be between 2 and 4 times the thickness of the strip being guided and controlled.

In an example with metal strip of 0.4 to 0.5 mm in thickness, the width of the groove in the free running guide rolls may be between 0.9 and 1.5 mm.

In order that the invention may be more readily understood one embodiment thereof will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a schematic front view from upstream showing the disposition of a strip feed mechanism in accordance with the invention; Figure 2 is a schematic view from the side of part of the mechanism of Figure 1; Figure 3 is isometric view showing the feeding mechanism of Figure 1 from the inlet side; Figure 4 is isometric view from above of part of the mechanism of Figure 1; Figure 5 is a side isometric view of part of the mechanism of Figure 1; and Figure 6 is a schematic sectional view of a guide roll in accordance with the invention.

Referring now to the drawings there is shown a strip feeding mechanism 1 for a stamp press machine 2 (not illustrated in detail).

The mechanism comprising two fixedly mounted rollers 3,4 one upstream of the other with respect to the incoming strip 5, the upstream roller 3 being freely rotatable in bearings and being an accurately machined roller of precisely known diameter formed of steel, whilst the downstream roller 4 is arranged to be connected to a driving motor 6 via a tooth-drive belt 7.The accurate roller 3 comprises the measuring/positioning roller of the driving mechanism and connects to a pulse encode 8 which,by magnetic or optical means for example, produces pulses in dependence upon rotation or partial rotation of the measuring/positioning roller 3, such pulses being passed by means of a lead 9 to an electronic control mechanism (not shown) which in turn, in a manner not shown but well known, controls the operation of the drive motor 6 for the driven roller 4 so as to ensure accurate movement therethrough of the strip 5 into the stamp press machine 2 and accurate disposition thereof within the machine for the appropriate press stamping operations.It is to be noted that whilst the measuring/positioning roller 3 has an accurate steel peripheral surface, that of the driving roller 4 is provided with a non-marking gripping surface comprised by a layer 10 of a resilient material such es synthetic rubber.

Mounted above the two fixedly mounted lower rollers 3 and 4 and mounted within a bearing carrying support block 11 at each end are two load rollers 12,13 each provided again with a non-marking gripping surface provided by a layer 14,15 of resilient material such as synthetic rubber.

The upstream load roller 13 is arranged in use to engage the measuring/positioning roller 3, whilst the downstream roll is arranged in use to engage the driven roller 4 to provide a drive nip on incoming strip 5 through the driving mechanism 1.

In the example of the invention illustrated, the strip is of light alloy material having one highly prepared reflective surface intended for use, after press stamping and subsequent machine operation, as reflective surfaces in lighting installation louvres surrounding the lamp thereof.

The support blocks 11 carrying the upper load rollers 12,13 are urged downwardly by means of four load springs 16 acting between an upper frame member 17 and the blocks 11.

The support blocks 11 themselves are attached to side block assemblies 18 by means of pivot pins 19, the side block assemblies 18 being moveable vertically within vertical slides 20 at each side. By such an arrangement a limited amount of two and from movement is possible of the upper rollers 12,13, and similarly a limited amount of forward and back movement is possible to accommodate variations from flatness of the strip 5 entering the mechanism.

The side block assemblies 18 carry a horizontal connecting plate 21 connecting them to which is associated a cam operating pressure release lever 22 for raising the side blocks 18 and support blocks 11 and hence the upper rollers 12,13 against the action of the load springs 16 to release the nip-drive on the strip through the feed mechanism at any time for any adjustment or correction that may be necessary.

By means of the apparatus hereinabove described, accurate control of the movement through the feeding mechanism of the strip is obtained by the direct contact of the measuring/positioning roller 3 with the underside of the strip 5 passing therethrough so that drive of the strip 5, and disposition within the succeeding stamping press 2 can be accurately provided. At the same time, since the drive of the strip 5, and the load roller 13 for the measuring/positioning roller 3, is by means of non-marking resilient surfaced rollers, no scuffing or marking from the rollers on the upper, highly prepared surface of the strip, will result during passage through the feeding mechanism.

As mentioned above, side control of the strip is a very critical area in the presentation of strip through the feed mechanism into the succeeding stamping press, and this is provided by means of a pair of side rolls 23 freely rotatable about a vertical axis and located, following freely rotating approach rollers 30, adjacent the entrance to the feeding mechanism 1, and (not shown) within the stamp press itself. Rolls 23 are disposed each side of the strip and including a peripheral groove 24 at the base of a V-shaped entry groove 24 in each roll, the groove being of a width between 2 and 4 times the thickness of the strip. Preferably in the embodiment illustrated the width of the groove 24, having parallel sides and a rounded base, is of the order of 1.25 mm where the strip engaging therewith and entering the feeding mechanism to the stamp press machine is between 0.40 and 0.50 mm.

It is to be understood that the foregoing is merely exemplary of strip feeding mechanisms in accordance with the invention and that modifications can readily be made thereto without departing from the true scope of the invention.

Claims

1. A strip feeding and measuring/positioning mechanism comprising two pairs of nip rollers through which the strip is arranged in use to be passed, being a first pair of rollers one of which is motor driven and the other of which is a load roller, both being coated with a layer of non-marking gripping material such as a synthetic rubber, the first pair being arranged to drive the strip through the mechanism, and a second upstream pair of rollers through which the strip is arranged in use to pass prior to passing through the driving pair of rolls, the upstream pair of rollers comprising one load roller provided with a layer of non-marking gripping material such as synthetic rubber, and a measuring/positioning roller comprising an accurately machined roller of known diameter connected to a pulse encoder device connecting in turn to a drive motor of the driven roller whereby to control the same in dependence upon predetermined rotation of the measuring/positioning roll and hence the disposition of strip being fed through the mechanism.

2. A mechanism as claimed in Claim 1 wherein the pairs of rollers are disposed in a horizontal plane, such that the strip passes horizontally therebetween, and the driven roller comprises a lower roller of the driving roller pair, and the measuring/positioning roller comprises a lower roller of the upstream pair of rollers.

3. A mechanism as claimed in Claim 1 or 2 wherein the upper load rollers of the two pairs of rollers are mounted in blocks downwardly urged by load springs upon the two lower rollers, the mounting blocks, carrying bearings for the upper load rollers.

4. A mechanism as claimed in Claim 1, 2 or 3 wherein the mounting blocks are pivoted on a side block assembly at each end which is vertically moveable within a vertical slide, thereby providing in operation flexibility of the disposition of the upper load rollers relative to the lower rollers to accommodate variations in the strip being fed therethrough both in a side to side direction, and in a forward and back direction.

5. A mechanism as claimed in Claim 1, 2, 3 or 4 wherein means are provided for raising the mounting blocks of the upper load rollers, against the action of the load springs, to lift them out of contact with the lower rollers to ensure a cessation of the driving of the strip through the mechanism for any necessary adjustment during operation.

6. Positional guide and control means for strip travelling towards and/or out of feeding mechanism therefore, comprising a pair of freely rotatable rolls disposed one on each side of the strip, the rolls being rotatable about axes normal to the plane of the strip and each being provided with a central peripheral groove therethrough of substantially parallel sides and disposed in operation such that the strip edges engage into the groove, the groove having a width arranged to be between 2 and 4 times the thickness of the strip being guided and controlled.

7. Means as claimed in Claim 6 with metal strip of 0.4 to O.Smm in thickness, wherein the width of the groove in the free running guide rolls is between 0.9 and 1.5mm.

8 Apparatus according to the invention substantially as shown in and as hereinbefore described with reference to the accompanying drawings.